Manufacture of zinc-sodium hydrosulfite.



UNITED STATE OFFICE GUSTAV 'MtINon, or GRIESHEIM, GERMANY, ASSIGNQB. To CHEMISCH'E-FABRIK GRIESHEIMfELEKTRON', OF FRANKFORT-ON-THE-MAIN, GERMANY.

- MANU ACTURE OF ZINC-SODIUM HYDliOSULFITE.

' N 0 Drawing.

quite ditlerentfrom the process in ac-- cordance with this invention. For instance solutions of sodium hydrosullites and solutions of zinc chlorid havebeen mixed together, or lyes of zinc hydrosulfite have been salted out with common salt. Another well known process consists in the preparation of a ditiieultly soluble ZlllC hydrosulfite, but this process is quite ditferent from that forming the object of the present invention, as in accordance with the said known process sulfites are treated, in the presence of water, with zinc dust and acid.

fate, sultite and sulfate).

I have found that it is possible to manufacture by a simple process a zinosodium hydrosullite. which is ditlicultly soluble and has a. high percentage purity,

.-\ccort.liug to this invention solutions of nude zinc lrvdrosullite and sodium hydrosultitc are mixed together. and in a short time a white crystalline salt separates out. which becomes thicker and thicker until the white mass 1l. .-llllltb' the consistcnty of thick pulp. The reaction takes place more rap idly if from the tir t the mixture be heated to, and maintained at. a temperature of from to centigrade. The yield of the salt from the .aqueous mother lye is almost equal to the theoretical yield. It is the double salt zinc-sodium hydrosnlfite with a small .amount'of impurities (thiosul The precipitated saltcan be. separated from the mother-lye by means of acqueous alcohol and then dried En vaimo by heating up to form to 703 centagrade.

Specification c! Letterx-latent. Application filed October 4, 1911. Serial No. 652,819.

Patented July 29, 1913.

It might have been anticipated that, in

accordance with the data of Bazlen Berz'cfite' 38, 1905. I. p. 1060, a. readily soluble double salt having the formula ZnNa. 0 would be obtained, but this is not the case, as a. ditlicultly soluble product is precipitated which contains one molecule of sodium hydrosulfite for about two molecules of zinc hydrosulfite. I f. more hydrosulfite be used, the excess remains in solution.

The process can be carried out as follows, but the invention is not limited to the precise details of the following example: 100 liters of zinc hydrosulfite lye containing 74: kilograms of ZnS. .O sodium hydrosulfite lye containing 33 kilograms of Na i O are allowed to run to gether into astirring vessel in which from the first the temperature is maintained at from (30 to (35 centigrade and at. this temperature the stirring of the charge is con-- tinued for about half an hour and the hot liquor is then filtered. After the saltobtained has been washed with aqueous alcohol it is dried "in menu at from (50 to 70 cent-igrade and a very good yield of a white stable double salt is obtained, containing about 90 per ccnl. of ZnS O It can re main exposed to air for weeks without being seriously affected.

I claim:

'1. The herein described process of producing a stable. high percentage and ditlicultly soluble inc-sodium-hydrosultite comprising stirring together solutions of zinchydrosultite and sodiu;n-hydrosulfite. while in a heated condition. and then separating the precipitated salt from the mother liquor.

The herein described process of producing a. stable, high percentage and ditticultly soluble zinc-sodium hydrosulfite comprising stirring together solutions of zinchydrosulfite and soditun-hydrosulfite in the proportions of about two molecules of the ZlllC salt to 1 of the sodium salt. while in a heated condition. and then separating'the precipitated salt from the mother liquor.

3. The herein described process of producing a stable. high percentage and dithcultly soluble zinc-sodimn which comprises stirrinc together solutions 2 t f v 1,068,522

In testimony whereof I lta s esignd my hyd l'd s u% te and sodium hydrosulfite f lithe p rop us of about two molecules of name to this specification in the presence of the zln' 1 one of th sodium-salt at a two subscribing-witnesses. t tempemtur'of alx'nit'GO to 65 C." until pre- 5 GUSTAV MUNCH. cipitu'tion of the diflicultly Soluble con} i \Vitnsses:

pound has taken place, angl then separating FRANZIIASSLAUHER,

Such compound from the 'inother liquor. En'wm DIPI'EL. 

